Sarah Paulson Shares Her Favorite Memory of Diane Keaton

Sarah Paulson says Diane Keaton pulled a move fitting of "The Godfather" himself ... always taking care of the little people working in the restaurants she patronized over the years.

Paulson remembered her late friend during an appearance on "Watch What Happens Live" after Andy Cohen asked her to share her favorite memory of Diane.

The actress takes a minute to think in the clip -- admitting she didn't realize Andy wanted to ask her about Diane -- before revealing she went to more dinners than she could count with Keaton ... who would always ask to go into the kitchen after a meal.

Instead of asking to meet the chef who prepared her food, Paulson says she went to the back to chat with the people who bussed tables and washed ditches ... giving them cash for all their hard work and having a conversation with them before leaving.

Paulson also says Keaton gave her great advice back in the day when her career wasn't going the way she wanted it to ... though she doesn't get specific.

As you know ... Keaton passed away last month at her Los Angeles home -- and, photogs captured a clearly distressed Paulson outside the place shortly after her death. Her family revealed she passed away from pneumonia.

Paulson fielded questions about her late friend during a red carpet premiere for her new show "All's Fair" ... telling Access Hollywood, "What you thought she was as a performer ... she was even more spectacular as a human being. And I was the luckiest person in the world to have had her in my life the way that I did."

Keaton was 79.